The present invention relates to telescoping seating systems; and more particularly, it relates to the row structure for a telescoping seating system.
Telescoping seating systems are, of course, well known; and they are in widespread usage in auditoriums, gymnasiums, arenas, and other areas, particularly where a location is desired to be used for more than one purpose. A telescoping seating system includes a number of row assemblies which may be extended for use or retracted for storage. In the use position, the row assemblies are arranged in tiered or stepped relation. That is, in the use position, relative to a lower row, the next rearward row is also higher so that the occupant of the rear row has unobstructed vision.
In the storage position, the rows are arranged in superposed relation--i.e. a lower row is nested beneath the next higher row so that all rows are generally vertically aligned. Although the rows may be interlocked in the use position for stability, the rows are normally independent of one another when they are moved between the use and storage positions. Typically, a lower row is extended first for use, and a lower is also retracted first for storage.
When referred to, the "length" of a row is the overall dimension from the left edge of the row to the right edge of the row when viewed in the position of an occupant, and the "width" is the fore-to-aft dimension (that is, in the direction of motion of the row). Because of the structural aspects of row construction, there are practical limits to the length of the row. A typical row length is in the range of 18-20 feet. Hence, if the dimension in which seating is sought is of the order of 80-100 feet, the rows are arranged in "sections", each section comprising a plurality of rows similar to the other sections, and arranged side-by-side to form the overall seating system. In the past, the seating sections were built in sequence--that is, one section was completed before the construction of the next section. The adjacent ends of corresponding rows were connected together for stability. It is desired, of course, that the corresponding rows of seating sections be horizontally aligned so that the occupant of the fifth row of one section can easily move to the fifth row of an adjacent section without obstruction or any change in the elevation of the footrest panel. Sometimes alignment systems such as tensioned cables and pulleys were used to prevent racking of the rows.
There has been a lot of design, engineering and testing in row structures for telescoping seating systems, and they have grown to be fairly sophisticated structures. To be considered, for example, is the fact that the same basic row structure is used for heights ranging from a foot or so to over thirty feet above the floor. Further, loading varies widely, and safety is of paramount importance and perhaps the more important design criterion in these systems.
Also to be considered are the various seating treatments which a manufacturer desires to offer to the market. These treatments vary according to use, cost and so on. In the past, the types of row structures have been classified into two major classes depending upon the seating offered. A bleacher type of structure which offers conventional bench type seating typically has that seating secured to the row structure and forming an integral part of it. The seating does not move relative to the row structure whether the row is in the use position or in the storage position. A second type of row structure, sometimes referred to as a chain platform structure, permits a wider variety of seating to be offered, and in this type of structure, the structure of the row is generally thought of as being independent of the particular seating.
In general terms, each row includes an understructure which typically may have two posts or columns which determine the height of the row structure, strapping or braces holding the columns together, and a wheel carriage at the bottom of each column permitting the structure to be moved along a floor. Modern row sections typically employ a metal riser beam connected to the top of the columns and forming the rear structural beam of the deck portion of a row structure. The deck also includes footrest panels which may be supported along their rear edges by a flange of the riser beam and forwardly projecting arms or supports also attached to the riser beam. The deck structure is typically cantilevered from the posts or columns of the understructure, and it may include, in the case of a chair platform structure, a forward structural member extending the length of the row structure and supporting the footrest panel, sometimes referred to as a nose beam.
The present invention relates particularly to the deck construction of the row structure for telescoping seating systems, and to the method of assembling the row structure. It has the particular advantage of forming an integral horizontal truss from the elements of the deck structure wherein the horizontal truss extends continuously for all corresponding rows of adjacent seating sections. This permits all corresponding rows to be moved as a unit between the extended and retracted positions, and it provides enhanced rigidity to the overall row structure.
A continuous horizontal slot is formed at the base of the rear riser beam and cooperates with the lower flange of that beam to receive and encapsulate the rear edge of the footrest panel. A similar encapsulating slot is provided by the nose beam for receiving the forward edge of the footrest panel. Support members are secured to the rear riser beam and extend forwardly beneath the footrest panels. The nose beam is secured to these support members by means of threaded fasteners. The width of the footrest panel (that is, the forward to rear dimension) is slightly greater than the corresponding dimension defined by the encapsulating slots when the nose beam is assembled to the support members. Thus, as the nose beam is fastened to the support members, with the edges of the footrest panels held by the encapsulating slots, the footrest panels are compressed. The footrest panel, the front and rear structural beams and the support members thus form a horizontal truss. This truss is continued between corresponding rows of laterally adjacent seating sections by extending the footrest panel to bridge across the joint between these adjacent sections. Thus, the horizontal truss is continuous and extends the complete length of the laterally adjacent rows. This truss is moved as a unit between the extended and retracted positions, and it adds a structural rigidity to the overall section which extends to adjacent sections.
The provision of a continuous horizontal truss of the type described herein has an advantage in systems which are extended and retracted using floor-engaging power units. Depending on the number and length of rows in the sections, it may be possible to reduce the number of power units, which normally are provided for each section, so that, for example, four power units may be employed for five sections. The rigidity of the horizontal truss which incorporates the footrest panel permits the rows of the section without the power unit to be carried along by the rows of the sections which are powered. Another advantage of the inventive system is the possibility of eliminating auxiliary alignment systems such as have been used in the past to prevent racking of the rows.
In the illustrated embodiment, the encapsulating slot on the rear riser beam is provided by forming a rib in the vertical web of the beam above its lower flange so that the rear surface of the slot is defined by the vertical web of the riser beam. By forcing the footrest panel into that slot under compression, the rear edge of the footrest panel is forced into engagement with a portion of the vertical web of the riser beam; and this structure maintains the web of the riser beam in a vertical plane and resists any tendency of the riser beam to twist or buckle under load. Thus, the structural rigidity of the riser beam is enhanced.
The nose beam is preferably an extruded metal form defining a forwardly opening slot which receives the hardware for fastening the nose beam to the forwardly projecting support members beneath the footrest panel, and an upwardly opening slot for mounting the seating. In this manner, the seating can be any one of many different varieties such as benches, individual chairs or ganged seating modules; and for each seating treatment, the seating can be adjusted and aligned so as to provide aisles at any desired location. Of great importance to the user is the fact that these aisles are formed at the footrest level (that is, the tread of the aisle is the same as the footrest panel for the row structure). In some prior commercial systems, the location of an aisle at the footrest level could not be changed without modifying the deck structure of a row.
Other features and advantages of the present invention will be apparent to persons skilled in the art from the following detailed description of a preferred embodiment, accompanied by the attached drawing wherein identical reference numerals will refer to like parts in the various views.